In the fall and winter these commensal rodents are more likely to enter a house seeking shelter when the nights get cold and the available supply of outdoor food (seeds and insects)become more scarce.
Mice require just a little more than ¼ inch to enter a structure. Rats just a little more than ½ inch is big enough to enter.
The most common of commensal rodents is the house mouse - and the signs to look for are gnaw marks, droppings (their droppings are very similar in size and shape to the sprinkles on donuts or cookies and fresh droppings are soft, moist and dark about 1/8-1/4 inch).
The most common rat is the Norway rat – and the signs of infestation gnaw marks, droppings (their droppings are about ½ inch with blunt ends), rub marks on vertical surfaces where they have travelled, and damaged goods.
All rat species and mice species have very good senses – with the exception of sight. Remember the nursery rhyme about “Three Blind Mice”? Well it is very true. Mice cannot see clearly beyond 6 inches. Rats’ vision is not much better. However, their sense of hearing, touch, and smell is very good.
Mice will travel about 20ft range from their harborage point. Rats about 100 – 150 ft from their harborage.
The key to any control program is pest identification, sanitation, harborage elimination and rodent proofing the building.